EXACT CHORUS:In the ultra short run—about 1 month—unintended inventory investment is reversed. In the very short run—about 9 months—other investment plans are made and begin to be carried out, which also affects output. This is a lag for interest rate changes to have their effect on investment and output. The very short run is where the Keynesian model struts its stuff. In the short run—about 3 years—the price level adjusts on a new track if the Fed hasn't done its job. In the long run—about 12 years—the capital stock adjusts to its steady-state level. This is according to the Solow Growth Model. In the very long run—over centuries—technology and population are the only drivers. The hockey-stick escape from the Malthusian Devil is the story.